your readings alone show how instable your tank ( and maybe even your testing methods) is/ are...I'm an old school dude, but the "new" trend of cycling a tank with ammonia is far and away, faster, and better on the fish ( ammonia does permanent damage to gills and internal organs).... for the next 6 months to a year, your tank is going to change almost daily.. you are going to go through stages of instability.... you are going to have "fights" with algae and bacteria.. before it settles up on the final permanent algae.. and only then if your parameters are good ( you will be testing for other compounds to keep the tank stable).. you must proceed slowly or you will be setting yourself up for disappointment and frustration.. you will know when your tank has cycled because the reading will be the same day after day for at least a week...listen to what people are telling you... every one of us here have been there...I've only been keeping salt water ( reef) for 9 months ( but have been keeping ponds and fresh water tanks for over 50 years) so what I'm telling you is fresh on my mind... I spent a year studying and preparing for the day I would start my first salt water tank.. something I had put off due to family and work obligations taking the time ( and money) I thought I would need... I have 6 fresh water tanks... I DO %20 water changes on them weekly and spend less than 3 hours of mainteneance on them weekly and they are pristine... I spend 1 -1/2 hours a DAY on feedings, maintenance and just observing on my 75 gallon reef tank ... reef/ salt water tanks require a lot of care if you want them to succeed,.... especially in the beginning....I know you are excited and can't wait the get things going... but I promise you.. go slow.. be patient and you'll enjoy the experience a lot more... your troubles will be few.. and your mistakes will be fewer... it may seem that folks here are harsh or overly critical.. they are not.. they want to help but we have seen this so, so many times.. just read through the threads in this forum alone and you will see what I'm talking about... good luck.. ask questions....look before you leap.. read before you buy.. this web site has more information than you could process in a life time... read.. enjoy and relax.. some day you'll be the one giving advise...